Automatic hardness tester



y 1951 r F. PEARSON ET AL 2,554,206

AUTOMATIC HARDNESS TESTER Filed Feb. 4, 1950 AMPL IF AMPLIFIER AMPLIFIERInventor: Fribh'lof L earson, A|T r on BSpawdin b, by [Q M His AttorneyPatented May 22, 1951 AUTOMATIC HARDNESS TESTER Frithiof L. Pearson,

Our invention relates to improvements in hard ness testing machines forefiecting the automatic operation of one variety thereof.

To obtain the hardness number of a test specimen on one form of hardnesstesting machine as presently constructed, the specimen is placed uponthe platform of the machine. The machine is manually operated to raisethe specimen to the penetrator or brale and continued to be operated tozero two indicator needles pivoted upon a dial of the machine. Ahandwheel is then operated to set the dial to zero.

Another manual operation of the machine applies the major load to thespecimen. When the hardness number is indicated by one of the indicatorneedles, the platform is lowered and the specimen is removed.

The object of our invention is to provide apparatus to make a hardnesstesting machine automatic so that the operator need only place thespecimen upon the platform and remove it after the hardness is recordedby the needle.

According to our invention, a motor is provided to drive the platform ofthe testing machine. When a specimen is placed upon the platform, anelectric eye switch starts the motor, which continues to run as thespecimen contacts the brale and until the dials are simultaneouslyzeroed. The motor is stopped by electric eye switches acting incombination with a solenoid switch having a pair of contacts, one ofwhich breaks the contact to the drive motor. The other contact energizesa solenoid brake on the motor and operates a switch energizing a motorto apply the major load to the workpiece. i

A pair of snap switches operated by the platform and by a levercontrolled by the load motor energize a solenoid control operating areversing switch of the drive motor. controlled by application of themajor load by the load motor to de-energize the drive motor while themajor load is being applied.

The platform is provided with limit switches to disconnect the drivemotor in case of overdrive of the platform while a solenoid operatedspring centered switch controlled by push buttons energizes the drivemotor for opposite drive when either limit switch is opened.

Reference is made to the accompanying drawing, the single figure ofwhich is a schematic view of an embodiment of our invention.

According to the drawing, switch connects leads 2 to a source ofelectric power 3. When switch is closed, the specimen 4 is placed upon aplatform and interrupts a beam of light be- Another switch is Saugus,and Almon E. Spaulding, Lynn, Mass., assignors to General ElectricCompany, a corporation of New York Application February 4, 1950, SerialNo. 142,495

3 Claims. (01. 73-83) tween light source 6 and a photoelectric cell 1.The signal from cell 1 passes through amplifier 8 to complete thecircuit from leads 2 to close solenoid switch 9 completing a circuitfrom leads 2 through switch It, contacts ll of switch I2, limit switchesI3 and 4 and contacts l5 of reversing switch It through motor I! toleads 2 thereby operating motor H. A worm l8 mounted upon the shaft ofmotor meshes with a gear i9 rotating upon frame 20 of the machine andprovided with an axial bore threaded to raise or lower screw 2| uponwhich platform '5 is mounted. When contacts I5 of switch l6 are closed,motor I! operates in the direction to raise workpiece 4 to meetpenetrator or brale 22.

As platform 5 is raised, an extension 23 of platform 5 operates a snapswitch 24 to open the connection between a source of power 25 and 26 andde-energize solenoid 21 allowing it to be withdrawn by spring 28. Motorcontinues to raise platform 4 to engage brale 22 to impose a minor loadupon specimen 4. The machine is provided with an indicator dial 29 uponwhich are pivotally mounted two indicator needles 30 and 3| connected bya lever system to brale 22.

Motor l1 drives platform 5 upward until indicators 3B and 3|simultaneously arrive at zero position indicating that the minor load isbearing upon workpiece 4. Slits are provided in dial 29 behind the zeropositions'of the needles 3!] and 3|, and light sources 32 are focusedthrough the slits upon photoelectric cells 33. These cells are connectedto amplifiers 34 and 35, the outputs of which are connected in series ina circuit between a solenoid 36 operating switch l2 and leads 2 so thatwhen the light beams from source 32 are interrupted by needles 3!! and3|, simultaneously the circuit is closed energizing solenoid 36 tooperate switch l2. As switch 12 is operated, contacts 31 are closed toenergize a circuit between power source 25 and 26, energizing solenoidswitch 38 to operate motor 39. Motor 39 is belt connected to a shaft 40upon which is mounted a cam 4|. In the position shown, cam follower 42of cam 4| supports a lever 43 pivoted at one end upon frame 20 and fromthe opposite end of which a weight 44 is suspended. As motor 39 rotatescam 4|, lever 43 lowers allowing the major load to be applied tospecimen 4 through lever 43 and a member 45 bearing upon brale 22.

A cam 46 is also mounted upon shaft 40 operating a follower arm 41 anddesigned to raise arm 41, during the time the major load is applied, tooperate switch l0 interrupting the circuit between leads 2 and motor l1.As arm 41 rises, it

operates a snap switch 48 to complete a circuit between source 25, 26through solenoid 49 actuating solenoid 49 to close contacts 50 of switchl6 reversing the polarity of motor I! in readiness for the return ofplatform to its original position.

When contacts 31 of switch l2 are closed, a circuit is completed betweensource and 26 through solenoid 5| operating motor brake 52 to stop motorll. During a single revolution of cam 4|, follower 42 is lowered fromthe position shown to allow the major load to be aplied to workpiece 4and is returned to the original position. During this time, indicatorneedle 3| records the hardness number of the specimen upon dial 29.

When indicator needle 3| leaves the zero position to indicate thehardness number, connection to solenoid 36 from line 2 is interrupted. Acircuit is provided energized by switch 53 operated by arm 41 to holdsolenoid 36 energized while the major load is applied to specimen 4.There is no discontinuity between the time solenoid 36 is energizedthrough amplifiers and 34 and through switch 53 since there is a timelag between the starting of motor 39 and the movement from zero ofneedles 30 and 3| due to cam 4!.

When the major load is removed by cam 4|, arm 41 drops to open switch 53and de-energizes solenoid 36. With solenoid 3B de-energized, switch l2operates closing contacts II in the circuit of motor I! and openingcontact 3'! releasing brake 52 and disconnecting load motor 39. Whenfollower 42 returns to its original position removing the major loadfrom specimen 4, arm 41 drops back allowing contact to be made in switchIll completing the circuit to motor I! which operates to drive platform5 down to its original position.

As platform 5 descends, projection 23 operates switch 24 to closecontact between source 25, 26 through solenoid 21 to energize solenoid21 causing it to actuate snap switch 48 opening the circuit betweensource 25, 26 through solenoid 49, de-energizing solenoid 49 to allowswitch [6 to close contacts [5 again reversing the polarity of motor I!to prepare it again to move table 5 upward. A projection 54 uponplatform 5 operates limit switches l3 or l4 to disconnect motor I! iffor any reason motor I! continues to drive platform 5 beyond the desiredupward or downward travel. A spring centered switch 55 connects theleads of motor I! to leads 2 and is operated bypush buttons 56 and 51operating solenoids 58 and 59, respectively, to reverse motor I! if itshould be disconnected by limit switches 13 and I4.

While certain specific embodiments have been shown and described, itwill, of course, be understood that various modifications may be madewithout departing from the invention. The appended claims are,therefore, intended to cover any such modifications within the truespirit and scope of the invention.

What we claim as new and desire to secureby Letters Patent of the UnitedStates is:

1. In combination, a hardness testing machine including a platform tosupport a test specimen, means for elevating and lowering said platform,a penetrator device for applying load to said specimen, means forloading said penetrator device and a device for indicating penetrationof said specimen, said indicating device including adial and-anindicator-needle pivoted upon said dial, and control means comprisingmotor means driving said elevating means connected to a source ofelectric power, photoelectric switch means responsive to the presence ofa specimen upon said platform to energize said drive motor, anelectromagnetically operated multiple switch means responsive to thepositions of said needle to energize and de-energize the electromagnetof said multiple switch, an electromagnetic brake mounted upon saidmotor, means controlling said loading means, contacts mounted upon saidmultiple switch to energize said controlling means and said brake inresponse to arrival of said needle at zero position, electromagneticreversing means controlling said drive motor, control means connected.to said reversing means responsive to operation of said loading meansto energize said reversing means and responsive to a limiting movementof said platform to de-energize said reversing means, limit switchescontrolling said drive motor responsive to travel of said platform todisconnect said drive motor at the ends of travel of said platform,separate reversing means controlling said drive motor and manual switchmeans controlling said reversing means to reverse the direction oftravel of said motor when deenergized by said limit switches.

2. In combination, a hardness testing machine having a platform tosupport a test specimen, means for elevating and lowering said platform,a penetrator device for applying a load to said specimen, means forloading said penetrator device, means for indicating the amount ofpenetration of said penetrator into said specimen including a dial and apair of indicator needles pivoted upon said dial, said dial having apair of slits therein positioned at the zero position of said needles,control means for said machine comprising motor means for operating saidelevating and lowering means, means for controlling said motor meansincluding a photoelectric switch, said photoelectric switch beingenergized when a test specimen is placed on said platform, a solenoidoperated multiple switch having pairs of contacts, switching meanscontrolling said multiple switch according to the position of saidneedles upon said dial, a solenoid load switch controlling said loadingmeans, a solenoid operated brake mounted upon said elevating motor, oneof said contacts closing to energize the solenoids of said brake andsaid load switch in response to simultaneous zeroing of said needles,means for reversing said elevating motor means, a pair of snap switchesone of which is responsive to the position of said platform, the otherof which is responsive to application of load by said loading meanscontrolling said reversing means, a pair of limit switches responsive toovertravel of said platform controlling said elevating motor, separatereversing means controlling said elevating motor, and switchescontrolling said separate means for operation of said elevating motorafter operation of said limit switches.

3. In combination, a hardness testing machine having a platform tosupport a test specimen, means for elevating and lowering said platform,a penetrator device for applying load to said specimen, means forloading said penetrator device and a device for indicating the amount ofpenetration in the specimen of said penetrator, said indicating deviceincluding a dial and a pair of indicator needles pivoted upon said dialand control means for said machine comprising motor means for drivingsaid elevating means connected to a source of electric power,photoelectric switch means responsive to the placing of a test specimenon said platform for energizing said drive motor, anelectro-magnetically operated multiple switch, a pair of photoelectriccells in series with the solenoid of said multiple switch and responsiveto zero position of said needles to energize and de-energize upon theshaft of said motor, solenoid operated loading switch controlling saidloading means, contacts mounted upon said multiple switch for energizingsaid loading switch with said needles in zero position, a spring biasedswitch to energize the solenoid of said multiple switch in response toapplication of said load, switching contacts mounted upon said multipleswitch disconnecting said drive motor when said load is applied, asolenoid operated reversing switch controlling the direction ofoperation of said drive motor, a first snap switch controlling thesolenoid of said reversing switch, said first snap switch beingresponsive to application of load to said specimen to actuate thesolenoid of said reversing switch, a solenoid positioned to operate saidfirst snap switch, a second snap travel of said platform when said motoris deenergized by said limit switches.

FRITHIOF L. PEARSON. ALMON E. SPAULDING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,762,497 Wilson June 10, 19302,120,381 Troxell June 14, 1938 2,142,253 Nunan Jan. 3, 1939 2,333,747Sklar Nov. 9, 1943 2,498,136 Rupley Feb. 21, 1950

